Haemorrhoids are one of the most common surgical diseases around the world. Various methods of treatment have been developed. The least expensive and most widely used method is rubber band ligation. It has been in use for many years and has proved to be the most effective.
In the known technique, a relatively long forceps is employed to hold the hemorrhoid, which is pulled through an O-ring forceps with a relatively long arm. The external part of the O-ring holds an already stretched rubber band. Once the forceps has grasped the hemorrhoid, the rubber band is fired from the O-ring by a simple pushing mechanism. The problems with the known technique include the requirement for two people to perform it, one to hold the anoscope and the other to apply the bands. This anoscope is needed to be able to visualize the haemorrhoids.
Because it is necessary to have two people to perform the technique, misfiring of the bands is frequent and readjustment is therefore required. Sterilization of the equipment between patients is essential, so many sets are needed.
As each patient usually needs 2 or 3 rubber bands to be applied, the O-ring must be loaded each time with a fresh band, which is a demanding task. Thus the O-ring forceps must be removed while maintaining the anoscope inside the patient, significantly extending the procedure time and requiring prolonged handling when contaminated.
A less common condition called oesophageal varices, which is dilated veins at the lower part of the oesophagus, is treated endoscopically in a similar way by applying rubber bands to the varices. One known endoscopic ligating instrument for this purpose was disclosed in 1998 in U.S. Pat. No. 4,735,194 (Stiegmann). The disclosed endoscopic ligating instrument has an outer tube mounted on the tip end of an endoscope and an inner tube axially movably inserted in the outer tube. A trip wire has an end coupled to the inner tube, extends through a biopsy channel, and has an opposite end projecting out of the endoscope and joined to a handle. When the handle is pulled, the trip wire is axially moved to move the inner tube rearwardly into the outer tube. A ligating O-ring made of an elastomeric material is expanded radially outwardly and mounted on a tip end of the inner tube which projects out of the front end of the outer tube.
The endoscopic ligating instrument is used as follows. The endoscope is inserted into the esophagus, for example, of a patient until the tip end of the inner tube covers a varix to be ligated. Then, after a region where the varix exists is drawn into the inner tube under suction or the like, the handle is pulled to move the inner tube rearwardly into the outer tube. The ligating O-ring is now pushed off the inner tube by the tip end of the outer tube, and contracted radially inwardly, thereby ligating the base of the target lesion. Since the blood flow to the ligated varix is blocked, the ligated varix hardens and may be removed. The removal of the ligated varix finishes the treatment of the patient.
However, since only one ligating O-ring is mounted on the inner tube, if a plurality of varices are to be ligated successively, then it is necessary, each time a varix has been removed, to take the endoscope out of the cavity, replace the inner tube with a new inner tube with a ligating O-ring mounted thereon, and then insert the endoscope back into the cavity for ligating treatment. For ligating a plurality of varices, therefore, the endoscope is required to be inserted into and taken out of the cavity as many times as the number of varices to be ligated. Such a ligating practice can cause considerable pain to the patient.
Another known endoscopic ligating instrument was disclosed in 1994 and 1995 in U.S. Pat. No. 5,320,630, U.S. Pat. No. 5,462,559 and U.S. Pat. No. 5,624,453 (Ahmed/Wilson Cook Medical). The device has been further adapted to provide a means of mucosal resection via rubber band ligation. This treatment has proved its efficiency in stopping bleeding from oesophageal varices. The rubber bands are loaded on a cartridge, which is loaded on the tip of a flexible fibre optic gastroscope. This is passed down into the patients' esophagus and the rubber bands are applied on the varices, which are drawn into the cartridge by the means of suction. The mechanisms used to fire the rubber bands are dependent on a thread applied over the cartridge body, under the rubber bands. Drawing the thread will fire the rubber bands. A plurality of rubber bands can be fired using this method. The same mechanism has been adapted to treat haemorroids in the Saeed ShortShot (ex Cook Medical).
The problem with this method is that time and a complex effort are needed to assemble the cartridges. That makes them expensive.
In 1995, European patent publication EP 0679368 (Hosoda) described an endoscopic ligating instrument for ligating varix. The instrument has an outer tube having a rear end in which the tip end of an endoscope is mounted. An inner tube with a trip wire connected thereto is axially movably inserted in the outer tube. When the inner tube is moved rearwardly, the inner tube is urged to move forwardly by a spring. Three ligating O-rings are mounted respectively at axially equally spaced positions on the outer circumferential surface of a portion of the inner tube which projects from the outer tube. Four arms extending forwardly from the outer tube are disposed respectively at circumferentially equally spaced positions over the outer circumferential surface of the inner tube. Each of the arms has teeth disposed behind the ligating O-rings, respectively, and having front pushing surfaces for pushing the ligating O-rings forwardly when the inner tube is moved rearwardly and rear slant surfaces for riding over the ligating O-rings and spreading the arms radially outwardly when the inner tube is moved forwardly. The endoscopic ligating instrument can ligate a plurality of varices successively when the endoscope is inserted in a cavity in the body of a patient.
In 2003 International patent publication WO 2003/099141 (Ghareeb) described a ligating device for applying successive elastic bands to tissue. In one preferred embodiment, the device includes a barrel having an opening into which the tissue can be drawn and a plurality of circumferential grooves around the barrel each for accommodating a respective ligating band. The grooves may be defined by ridges on first and second coaxial tubes respectively, the second tube being reciprocal relative to the first tube so that when the second tube advances towards the front end of the barrel its ridges push the bands forwardly so that they ride up over the ridges of the first tube to each lie one groove nearer the front end, the foremost band being pushed off the front end of the first tube onto the tissue. When the second tube retracts away from the front end the bands ride up over the ridges of the second tube to remain in their advanced positions.
In 2006, United States patent publication US 2006/259042 (Ali Hassanien) described a device for multi-ligation of veins of the haemorrhoid which comprises a front part including a fixed pipe surrounded by a movable pipe, a triggering cylinder with a triggering handle of elongated cylinder construction connected between the rear of a third part and the front part, and the third part being a rear part or mechanical handle part comprising a cylinder and handle for holding the device and a mechanism including the handle for effecting suction of veins into the front part of the device by pulling the handle with a connected piston backward.
Also in 2006, British patent publication GB 2426459 (Mihssin) described a single use haemorrhoid multi rubber band firing device which delivers up to four rubber bands in one application. The device may comprise an inner tube with four bands mounted at one end, an outer tube, a rotating spool, suction source and a suction port which may be blocked by a finger. The bands may be advanced by rotating the spool over a threaded part of the inner tube to advance the outer tube. The contact area between the bands and the outer tube may be lessened to reduce friction. The rubber band may have four protrusions on one side or it may be doughnut shaped to reduce contact with the inner tube and act as spacers between the bands.
The device described in WO 2003/099141 (Ghareeb) above has had some commercial use. However, the Ghareeb device suffers from a number of disadvantages. The ligating bands are all pre-stretched to a wide diameter which, when left in this state for a period of time, impairs the capacity of the band to return to the original internal diameter which it had prior to loading on the device. This in turn impairs the capacity of the band to satisfactorily ligate tissue, with the band either falling off prematurely or not achieving the desired effect on the tissue. Furthermore, the end of the device is comparatively large, obscuring the view through the proctoscope of the practitioner when applying the bands. The delivery of the bands can be unreliable, particularly once a lubrication gel has been applied, because the pusher teeth can slip under the bands and not fire the end band or advance the successive bands into the next circumferential groove.
The Mihssin device described above also suffers from a number of disadvantages, primarily that the bands are not satisfactorily spaced and frequently fire multiple bands at once.
The Saeed ShortShot ligator, requiring the use of threads to dispense the bands has similar problems to the Ghareeb and Mihssin devices in that the threads often do not progress the ligating bands in a uniform manner with the result that either no band or multiple bands are fired with a single shot.
The present invention enables the provision of a device for applying successive resilient ligating bands to tissue in a manner which reduces or overcomes the disadvantages of the prior art devices.